Problem: ${9 \div 0.8 = {?}}$
Answer: $ {9 \div 0.8 = 9 \div \dfrac{8}{10}} $ $ {\phantom{9 \div 0.8} = 9 \div \dfrac{4}{5}} $ Dividing by a fraction is the same as multiplying by the reciprocal of the fraction. $ {9 \div \dfrac{4}{5} = 9 \times \dfrac{5}{4}} $ $ {\phantom{9 \div \dfrac{4}{5}} = \dfrac{9 \times 5}{4}} $ $ {\phantom{9 \div \dfrac{4}{5}} = \dfrac{45}{4}} $ $ {\phantom{9 \div \dfrac{4}{5}} = 11.25} $